The radius is one of two long bones found in the human forearm. The radius, like other bones, is susceptible to a variety of fractures and other dislocations. For example, distal fractures of the radius are a common result of forward falls, with the palms facing downward, particularly among the elderly. In such falls, force exerted on the distal radius at impact frequently produces dorsal displacement of one or more bone fragments created distal to the fracture site. Unfortunately, internal fixation of such dorsally displaced bone fragments using bone plates has proved problematic.
Fixation may be performed dorsally. In this approach, a surgeon may apply a reducing force on the fracture by attaching a bone plate to the dorsal side of the radius. However, unless the bone plate has a very low profile, dorsal tendons overlying the bone plate may rub against it, producing tendon irritation or even tendon rupture.
Alternatively, fixation may be performed volarly. In this approach, a surgeon may attach a bone plate to the volar side of the radius. The volar side of the radius may be more accessible surgically and defines a distal pocket in which the distal portion of the bone plate may be disposed. Accordingly, the bone plate may be less obtrusive and may produce less tendon irritation with placement, even if the bone plate is thicker and sturdier.
Despite the potential advantages of volar fixation, attachment of the bone plate to the volar side of the fractured radius may complicate reduction of the radius. The distal radius of elderly patients in particular generally contains porous bone of poor quality. Accordingly, bone screws inserted into the distal radius through openings in the bone plate may not achieve enough purchase in the bone to hold distal bone fragments in position against the bone plate. Moreover, these bone screws may be even less effective at gaining enough purchase to pull bone fragments volarly toward the plate to aid in reduction of the fracture. In one alternative volar strategy, a bone plate with threaded openings is employed. Pins having a threaded region near their heads engage the threaded openings to fix the angular positions of the pins relative to the bone plate. These fixed pins are configured to restrict movement of bone fragments through contact with the fragments. However, the pins may be ineffective for pulling bone fragments volarly against the plate and for restricting movement of distal bone fragments after reduction. Thus, there is a need for an alternative strategy for reducing and fixing radial fractures, particularly in the elderly.